Road construction is increasing time to time, causing the demand for paving blocks to boost. On the other hand, the metal casting industry is also experiencing an increase, which negatively impacts the form of slag waste with a high enough silica content. Therefore, it is hoped that the hydration process between cement and fine aggregate forms an interface or maximum strength. This study aims to determine the effect of using slag as fine aggregate with replacement variations of 0%, 45%, 50%, 55%, 60%, and 65% of the paving blocks’ content weight and compressive strength. This research conducted experimental quantitative descriptive methods. In this study, the independent variables consisted of slag replacement variations of 0%, 45%, 50%, 55%, 60%, and 65% of the paving block volume and the dependent variables were compressive strength. Based on the research results, the use of slag with replacement variations of 0%, 45%, 50%, 55%, 60%, and 65% of the paving blocks’ volume could affect the paving blocks’ content weight and compressive strength. Paving blocks with the replacement of slag produced normal content weight in all percentages, and produced maximum compressive strength value was 42 MPa at 50% slag replacement of the paving blocks’ volume.